Trailer online for Valve's Portal

There is a trailer online for Portal, a new game which will accompany Half-Life 2 - Episode 2.

The game looks to be incredibly different from anything that we've seen before. In the game, there are no weapons except for a gun which creates portals. You can create two at a time, and move between them, or have others move between them.

The game will come bundled free with Episode 2, and Valve's Gabe Newell says that it leverages their distribution advantage with Episodic gaming - when the prices are smaller, people are willing to try something new.

Shacknews describes the game thus:
&quot;For example, the player was creating portals underneath enemies, who would then fall out of another portal onto an enemy in another room. Since objects retain momentum after passing through portals, they can essentially be launched great distances: if one portal is on the ground with its &quot;opening&quot; facing up, and the other portal is on a wall with its opening facing horizontally, dropping an object from a great height into the portal on the floor will send it shooting horizontally out of the other portal at the initial speed it had reached just before entering the first one. It is also possible to use such tricks for the player to shoot him or herself across great distances. Portals can even be created by shooting the gun through other portals.&quot;